Miniaturization is the recent trend in analytical chemistry and life sciences. In the past two decades, miniaturization of fluid handling and fluid analysis has been emerging in the interdisciplinary research field of microfluidics. Microfluidic applications cover micro arrays, DNA sequencing, sample preparation and analysis, cell separation and detection, as well environmental monitoring. The use of microfluidics principles for these applications attracts interest from both industry and academia. Some of the benefits achieved to date include the required use of only small amounts of sample and reagent, less time consuming procedures at a lower cost and higher throughput.
New microtechnologies and components have often been driven by the pharmaceutical industry's demand for high quality medicines produced at a rapid rate and a lower cost. In (bio)chemical and biological applications, miniaturization offers a solution to several challenges including increasing throughput, allowing automation, and decreasing costs by reducing the amount of expensive reagents used. In addition, miniaturization promises higher selectivity, higher yield, fewer byproducts, efficient heat management, and increased process safety.
Numerous designs are known for performing these microfluidic operations in conjunction with particular protocols. For example, by applying appropriate voltage gradients, a sample volume in which certain ions of interest reside can be delineated within a small volume, often referred to as a plug. This operation is important in separation techniques such as capillary electrophoresis (CE) in order to attain a high concentration of sample components to be detected in a sample plug, with minimal loss of sample within the volume preceding or following the plug. There is a need for improved sample formation procedures and microfluidic apparatus that can provide sharply delineated volumes of material for analysis and separation of its components.